Machine for chasing pipe-threads and like work.



W. T. JUHNSTON. MAGHINE Pon GHASING PIPE THREADS AND Lm: WORK.

APPLICATION FILED JULY 24, 1902.

Patented 0st. 26, 1909.

2 SHEETS-SHEET L W. T. JOHNSTON. R cHAsNG my: THREADS AND Lm". wenn.

APPLICATION FILED .TULY 24, 1902.

Patented Oct. 26, 1909.

2 SHEETS-SHEET 2 MACHINE F0 NVENTOR.

(y ATTORNEY.

WILLIAM T. JOHNSTON, OF NEWPORT, KENTUCKY.

MACHINE FOR CHASING PIPE-THREADS AND LIKE WORK.

Specification of Letters Patent.

Patented Oct. 26, 1909.

Application led July 24, 1902. Serial No. 116,837.

To all whom it may concern:

Beit known that I, WILLIAM T. JOHNSTON, a citizen of the United States, and a resident of the city of Newport, in the county of Campbell and State of Kentucky, have invented certain new and useful Improvements in Machines for Chasing Pipe-Threads and Like lVork, of which the following is a specification.

The several features of my invention and the various advantages resulting from their use conjointly or otherwise, will be apparent.

from the following description and claims.

In the accompanying drawings making a part of this specification, and in which similar letters of reference indicate corresponding parts,-Figure l is a view partly in side elevation and partly in section of a machine illustrating my invention, the view also showing the application of my machine to a pipe for chasing one kind of pipe threads. The section is a vertical longitudinal one taken in a plane of the axis of the cylindrical portion of the machine; and shows the pipe upon which threads are to be chased in like section. Fig. 2 is a view of that collar which is on the left hand in Fig. l, and that side of the collar being shown which faces toward the left in Fig. 1. In this Fig. 2, the front ends of the draw rods and their handles for working the feed blocks are shown. The front ends of the rods and their nuts for moving the collars to operate the toggles and their feet, whereby my machine is held to the pipe on which latter the tool is to operate, are shown. The sleeve on which these collars slide is shown in end elevation. Fig. 3 is a View partly in elevation and partly in section, the section being a vertical cross one, taken in the plane of the dotted line 3, 3, of Fig. l, and looking at that side of the section which faces toward the left in Fig. l. Fig. l is a detail partly in elevation and partly in section, illustrating the construction of a feed block and its operating rod. Fig. 5 is a front or rear view of any one of the feed blocks. Fig. 6 represents a rear elevation of the slide rest and the tool holder and the bracket for enabling the tapered sleeve to cause the cutting tool to make a similar taper on the pipe to be operated upon. This figure also shows an elevation of the adjacent part of the large gear wheel with which this slide rest is combined; the sleeve concentric with the large gear wheel and on which the latter is fixed is shown in elevation, While the shaft within the sleeve is in section. Fig. 7 represents a front elevation of the slide rest and the mechanism for its operation, and the adjacent part of the large gear wheel with which the slide rest is combined. Fig. 8 represents a horizontal section of the slide rest, the adjacent portion of the large gear wheel, and of the tool holder, the section eing taken in the plane of the dotted line 8, 8, of Fig. 1, that side of the section being seen which, in Fig. 1, would face toward the top of the sheet of drawing. Fig. 9 is a front elevation of the clamping device which is to be fastened to the pipe on which the work is to be done, and when so fastened is for holding the crank bearing bar in a stationary position. Fig. 10, Sheet 2, is a view partly in elevation and partly in section o a modification of. certain features of my invention. This figure shows a simple machine for cutting a thread on small pipe. Fig. 11, Sheet 2, is an elevation of that end of the device shown in Fig. 2, which faces toward the right in that figure.

I will now proceed to describe my invention in detail.

I provide a sleeve A made of metal, preferably of cast iron. The sleeve is for insertion within the pipe on which the threads are to be cut or chased, and has means for enabling it, when within the pipe, to be locked fast to the latter at a desired locationl and for enabling the sleeve to be unlocked, as occasion demands. The means which I prefer to employ are as follows: I combine with the sleeve two or more sets of toggles. And to properly maintain the sleeve centrally within the pipe while locked therein, I provide three toggles, B, E, in each set, located at equal distances apart around the sleeve A. The inward or sleeve end of each toggle is connected to the sleeve, and preferably by a lug or lugs B3, this connection being effected by a pivot B2. The outer limb or shoe E of the toggle is pivoted to the inner limb B thereof by a pivot E2. The outer end of this shoe E is elongated as shown and fiat in the direction of such elongation, to adapt this end of this shoe for its entire length to meet and frictionally engage with the inner surface of the tube to which my machine is applied, and upon which a thread is to be chased.

The collars C, C, are located on the sleeve A and are slidable thereon. One of these collars C is outside of one set of toggles and the other collar is outside of the other set of toggles. Each collar bears against the limbs B of its respective set of toggles. That part of the collar C which thus bears against the limbs is beveled and concaved substantially as shown, thereby enabling the part C2 of the collar to bear against the toggle limb B far enough from the pivot B2 to get a leverage on the shoe E through the agency of the limb B. The collars are moved toward each other or away from each other by suitable means, preferred means being the bolts D, three in number, each bolt passing through its adjacent collar in a line parallel to the axis of the sleeve. Each bolt has a head or end D2 outside of one of the collars, and this head prevents the bolt from being drawn through that collar C. On the other end of each bolt D and outside (in front) of the adjacent collar is a nut D3. These nuts D3 are preferably located at the front collar, and the heads D'l will then be at the rear of the rear collar.

After the sleeve A with its mechanism is placed within the pipe Z on which threads are to be chased, then by screwing the nuts rearwardly, the collars are approximated and the free ends of the limbs B of one set of toggles are approximated, and the shoes E forced against the inner surface of the pipe to be held, and thus my machine is held firmly in place relatively to the pipe, as will more fully hereinafter appear. When it is desired to detach my machine from the pipe, the nuts D3 are unscrewed, thereby allowing the toggles to flex, and relinquish their pressure on the pipe.

As will be hereinafter evident, the machine is capable of chasing threads on pipes of different diameters, namely: of any diameters within the ordinary limits of certain standard sizes. The pipe Z may illustrate any one of such pipes. The toggles are obviously adapted to engage the pipe and firmly hold the sleeve A in the pipe whether the latter be of a larger or smaller diameter.

A shaft F extends through the sleeve A. At its rear end, it is suitably secured to the end of the sleeve A so that -it cannot slip lengthwise in this sleeve A. Preferred means for this purpose consist of the collar A2 having an annular projection A3 adapted to enter the interior of the sleeve, while the remainder of this ring or collar abuts against the end of the sleeve. Bolts A4 secure the collar A2 to the end of the sleeve. The end of the shaft F is diminished, so as to present a diminished portion or tongue A5 leaving an offset A, which abuts against the inner side of the collar, While the tongue A5 occupies the space within collar A2. Farther out, the tongue A5 terminates in a concentric screw bolt A7, and on this is a washer A8, and a nut A. The latter being screwed to place, holds, by means of the collar, the shaft F and prevents it from moving relatively to the sleeve A.

The front end of the shaft F extends forward beyond the front end of the sleeve A, and is there connected to a crank bearing bar or arm G. This bar carries the shaft H duly journaled in said bar. The shaft H is supplied at one end with a hand crank I, and at the other with a pinion gear J. The latter engages a large gear Wheel K, which carries an adjustable slide rest L. This slide rest is provided with a tool holder M, adapted to carry a chasing tool ground or otherwise formed to proper shape for cutting standard or other threads, and also for carrying a tool for making a smooth cut on the end portion of the pipe when such end instead of engaging a female screw, is to have a flange, etc., shrunk thereon. This tool holder M has the usual set screw M2 for enabling the chasing tool T to be adjusted to or from the shaft F as necessity demands. The shaft F although concentric with the sleeve A, is of smaller diameter, and between this shaft and this sleeve is located a hollow shaft N, which is bored to fit over the shaft F, and turned to slip into the sleeve A. This hollow shaft N is provided with threads and to adapt the machine to cut several kinds of threads, namely: coarser or finer threads as desired, it is provided with as many dierent sets of threads as it is intended shall be chased by the machine. Thus in the illustrative drawing, I have shown three sets of threads. The thread O is eight threads to the inch (same as the standard pipe thread); the thread P is eleven and one-half threads to the inch, and thread Q is twenty threads to the inch. The thread P is intended to adapt the machine to cut threads for well casing. The thread Q, while adapting the machine for chasing threads as aforementioned, is also intended to enable the machine by means of a proper 110 tool to take a smooth cut off the end of the pipe, for enabling' flan es to be shrunk thereon. Of course the ot 1er threads O and P could also be utilized in like manner, to the extent of their capacity. The connection be- 115 tween the cutting tool T and any one of these threads is preferably made by the following means :-Each one of the sets of threads O, P and Q is provided with a feed block R. The inner end of this block has 120 teeth adapted to engage the thread of the set by which it is to be operated. The block extends down through an opening R2 in the sleeve A. Vhile the block is free to slide in this opening, it yet closely fits it. The 125 upper part has a recess R3, and across this recess extends a rod R4. Through the opening R5 thus formed between this rod and the bottom of this recess, extends a sliding rod S. This rod S has an incline S2. With the 130 machine in the direction shown, when the rod S is moved toward the rear of the machine, the block R is depressed and its teeth engage that one of the set of threads which is adjacent. In the drawing, that one of the set is O. When the rod S is retracted, the block R is lifted away from the thread as O, it heretofore engaged. The rod S slides through suitable abutments. Such abutments S2 are shown and are fixed to the sleeve A. Toward the front, the rod S passes through the front collar C and farther forward is provided with a handle S2.

As there are shown three threads, viz: O, P, Q, and a block R for each, sothere are three rods, one for each block, and all are similarly constructed and supported by their own abutments, and each passes through the front collar. Like the toggle joints, these blocks and rods are respectively, preferably, disposed at equal distances apart around and upon the sleeve A.

The large gear wheel K is fixed to the hollow shaft N, and both are rotatable upon the shaft F.

Means for depressing the cutting tool T after making a cut, so that as it follows the screw threaded depression already made by it, it shall icut that depression deeper, consist of the feed screw U which when rotated in the proper direction depresses the tool holder M and the tool T.

The projection W located on the slide rest L is provided for cutting standard tapers required for pipe threads, etc. The slide rest is provided with suitable mechanism which compels the tool to follow the taper A10 shown on the adjacent end of sleeve A, when such mechanism is put into use.

The preferred construction of the slide rest and the means for operating it are as follows The slide rest L moves between beveled guides K2, located within an enlarged radial arm K3 of the large gear wheel K, see Figs. 6, 7 and 8. A part of the side edge portions L2 of the slide rest L are beveled to lit the bevels of the guides K2, and the remainder L2 of such edge ortions extend out beyond the beveled portions L2, and rest against the adjacent rear portions of the guides K2. A plate L4L secured to the front of the slide rest L, preferably by a screw L5, overlaps the front edges of the guides K2, K2. Thus the slide rest, by means of the edges L3, L2', at rear, and the plate L4 in front, embraces the guides K2 in front and rear, and is securely held to the guides. At the same time, the slide rest is free to slide verticallyI between the guides. A suitable spring presses the slide rest downward, and when permitted to do so will always keep the slide rest at the bottom of its line of movement. The preferred kind of such spring is a rubber block L located at the top of the guideway space between the upper end of the slide rest and the rim of the gear wheel. When not interfered with, this spring will press the slide rest L downward, and it will therefore press the tool T down against that part of the pipe Z where the thread is to be chased. When it is desired to elevate the slide rest and thus keep the tool T from contact with the pipe, I use the following referred means. The lower end of an arm carries a short arm X3 pivotally fixed to it. The arms X, X3 are fulcrumed at X2 to the slide rest. The free end of the arm X3 rests upon a bottom or plate L7 which may be the bottom of the guide space in which the slide rest moves. The upper end of the arm X carries a handle X2. By moving the handle X2 to the right in the direction of the arrow on the curved dotted line, the lower arm X2 is forced against the bottom L7 of the space in which the tool rest moves, and forces this tool rest L u ward and compresses the rubber (spring) lock. Thus the tool T is raised, and remains raised while the length of the arm X3 alines with the long axis of the guide rest. To lower the tool rest and to allow the spring to act again, the arm X with arm X3 is returned to its first named position. In operation, the arm X3 acts after the manner of a cam.

In operating my device, it is necessary that the pipe should be stationary, and the crank bearing bar G should also be stationary. For heavy work, a device for keeping the bar Gr stationary may be advantageously employed. A preferred device for this purpose consists of a suitable clamp. One de scription of such clamp is illustrated and consists of a curved shank Y having at one end the diverging arms Y2, Y2, to the free ends of which a cord or chain Y3 is connected. The connection of this chain to one of these arms is by a screw bolt Y4 passing through this arm and held in place by a nut Y2. As the nut is screwed upon the bolt, the latter moves through the arm Y2 and draws the chain, and vice versa. The other end of this shank Y is provided with the fork consisting of the arms Y, Y0.

In practice, the pipe is embraced between the arms Y2, Y2, and the chain Y3, the latter being tightened upon the pipe. The fork Y, Y, receives the bearing rod G2. The

grasp of this device Y2, Y2, YS, upon the the toggles. These latter engage the pipe and fixedly secure the sleeve to the pipe concentrically. The arms Y2, Y2 of the shank Y are now applied to the pipe, so that the latter rests in the fork between them, the forked end Y, Y of the shank Y being at the same time located so as to receive the bearing G2, the gear wheel K and the crank bearing bar G with shaft F, etc., being as already mentioned located in a proper position relative to the pipe Z. The tool holder is therefore now in position for the tool T to begin the work of chasing threads on the pipe Z. It having been determined which one of the threads O, P, or Q is to serve as a pattern for the thread to be chased on the pipe, that one of the feed blocks which is adjacent to said pattern thread is advanced into engagement with the latter. I accomplish this advance by drawing forward the sliding rod S of this feed block. The feed block bein T in engagement with the patternA thread, and the tool T having been vertically adjusted in the tool holder, the crank I is now turned, thus rotating the pinion gear J. The latter rotates the large gear wheel K which, in sequence, rotates the shaft N and, of course, rotates its pattern threads O, P and Q. That one of these threads in engagement with its lfeed block R operates to move this feed block R rearward, viz: toward the right hand in Fig. 1, and thereby moves the shaft N correspondingly rearward upon the shaft F, and with and by the sleeve is moved the gear wheel K, and also, of course, the slide rest, and tool holder, and tool T forward. As the large gear wheel K is turned, it will also move the slide rest and tool holder and tool with it around, and the tool will consequently move around the pipe Z, the cutting edge of the tool resting upon the outer surface of the pipe Z.

Inasmuch as the large gear wheel K has two movements, namely: a rotary one, and a rearward one, the latter being in lines or plane parallel to the aXis of the shaft F, the tool T will have like movements. Therefore it will move around the pipe Z, and will also move rearward toward the rear end of the pipe, in a spiral corresponding to the thread on that pattern O, P or Q which is in engagement with its feed block. As the spring Lfi of the tool rest presses the tool holder and its tool T sufficiently to cause the latter to chase, e'. e. cut a groove or channel in the peripheral surface of the pipe Z, the tool will cut such thread. Ordinarily the cut made by said tool in passing around the pipe Z will not be sufficient, that is to say, the thread will not be prominent enough. The operation of thus cutting the thread is repeated as often as necessary until the groove is cut sufficiently deep and the threads are consequently prominent enough. The mode in which this operation is repeated, is no doubt obvious, but to be s ecific, such mode is as follows: The thread iiavng been chased around and around the pipe Z as far rearward as desired, the too T is elevated or moved away from the pipe Z and held away by moving the arm Xa downward and to the left, so that its length alines with the length of the late H. This last operation compresses tie spring Le and moves the slide rest toward the rim of the wheel K, and with it the tool holder and tool, and at the same time compresses the spring L". The arm X3 will now continue to thus hold the tool away from the pipe Z. The operating feed block R is thrown out of engagement with its pattern thread, by sliding the rod S rearwardly. The hollow shaft N with its threads O, P and Q is now free to be slid, and it is now drawn forward, sliding within the sleeve A and upon the shaft F. As it is drawn forward (i. e. toward the front or left hand end of the machine, Fig. l), the large gear wheel K, and its operating means, and the slide rest and tool holder and tool T also move forward with it. When the tool T has arrived at and over the front end portion of the pipe Z and in a plane close to that of the edge of this pipe, the toggle X, X3 is moved, so as to assume the position shown in Fig. 7, and the spring L thereupon immediately moves the tool T radially inward toward the axis of the sleeve N and brings its working point, z'. e. cutting edge into contact. with the pipe Z, substantially as shown in Fig. 1. The same feed block R heretofore used is now thrown into engagement with its pattern thread. The feed screw U is either now or before the tool T is allowed to engage a second time with the pipe Z, turned so as to advance the tool holder and tool T toward the pipe Z a sufficient distance to cause the tool to press against the pipe Z hard enough to cut the groove as much deeper as it is proper the groove should be deepened at this second operation. The wheel K is now rotated, and the tool T moves forward around the pipe Z in the spiral groove it has -cut before, and cutting said groove deeper. These aforedescribed operations for cutting the thread, disengaging sleeve A, retracting the parts, for making a new cut, etc., are repeated until the screw or spiral groove is cut sufficiently deep, and the thread on the pipe becomes what it. is desired to be. Inasmuch as the standard pipe threads tapered from that edge of the pipe where the thread begins, and the tapers are standard ones, the projecting piece or bracket W on the slide rest will be employed for this purpose. The adjacent end of the sleeve A is conformed to the standard taper. The foot of the bracket W rests upon this tapered end of sleeve A and as the tool T advances chasing the thread on the pipe, the tapered surface of the sleeve A through the agency of ythisbracket, and the slide rest, continually forces the tool T away from the pipe Z, as the taper on sleeve A effectuates, suiiciently to cause the tool to cut the screw of the standard taper.

When a straight thread (not tapered) 1s to be cut, the slide rest is raised, preferably by a strip of steel, inserted below the slide rest, in the space L7 at the bottom of the space in which the guide of the slide rest moves. When instead of a thread to be chased, a smooth cut is to be made on the end portion of the pipe, the character of the cutting tool will be changed, such change being well understood in the art to which my invention appertains. For cutting threads on small pipes, it is unnecessary to have the gears J and K. In the event of dispensing with these, the slide rest is preferably arranged in a straight bar, and is turned by a handle or handles This construction dispenses with the shaft F for holding the unnecessary arm G, etc.

Ihere only one kind of thread is required, the tracer thread or pattern A12, being the teeth shown at O and P and Q of Fig. 1 can be cut on the taper A1 of sleeve A. The bearing W should then have teeth 72 in that side of it which bears against the taper A10, and the teeth W2 of this bearing W engage the teeth A12 on the part A10, A12. Thus the part A10 A12 then acts to feed the thread tracing tool T forward, and also cuts the thread on the end portion of the pipe in a taper, substantially like the taper of the part A1, A12. When desired in this connection, the taper of the part A10, A12 ma be omitted. My invention can be employe for facing the ends of pipes.

Where in the claims I allude to the tool or mechanism for tracing threads, I desire it to be understood that such term includes also tool for cutting z'. e. shaving off or reducing the outer peripheral surface of the end of the pipe, for enabling it to be connected to another pipe.

What I claim as new, and of my invention and desire to secure by Letters Patent,

along the pipe, and bolts passing through the rings and carrying nuts adapted to move the rings against the arms B, and force the feet E against the pipe for clamping the sleeve to the pipe, and means in connection with this sleeve for supporting the mechanism for holding the cutting tool and for causing the same to revolve, substantially as and for the purposes specified.

2. In a mechanism for tracing pipe threads, a sleeve adapted to enter and be within the pipe to be operated on, a series of clamps located on the sleeve, and means for making them engage the pipe and hold the sleeve, a shaft within this sleeve carrying a thread having the pitch of the thread to be traced on the pipe, a feed block R carrying a female thread and held between guides of the sleeve, means for moving the feed block to and from the male thread of the shaft, and a rod for o erating such last named means, substantially as and for the purposes specified.

3. In a mechanism for tracing pipe threads, a sleeve adapted to enter and be within the pipe to be operated on, a series of clamps located on the sleeve, and means for making them engage the pipe and hold the sleeve, a shaft within this sleeve carrying -a thread, having the pitch of the thread to be traced on the pipe, a feed block R carrying a female thread and held between guides of the shaft, the abutment S3 adapted to receive the rod S near its incline S2 and fixed to the shaft, and rod R2, and rod S, having incline S2, located in position with said abutment and rod R4, and having a front support, substantially as and for the purposes specified.

4. In mechanism for tracing pipe threads, the sleeve A provided with clamps E, B,

voted at B2 to the sleeve, and rings C slidable on the sleeves and against the clamps, and means for causing the rings to operate the clamps, a shaft within this sleeve carryin a screw thread, having the pitch of the l thread to be traced on the pipe, a feed block R carrying a female thread, and slidable between guides of the shaft, and adapted when advanced to engage the thread of the shaft, a rod S sliding in the forward ring C, and means adapted to enable this rod to move the feed block to and from the male thread of the shaft, substantially as and for the purposes specified.

5. In mechanism for tracing pipe threads, the sleeve A provided with clamps E, B, pivoted at B2 to the sleeve, and rings C slidable on the sleeves and against the clamps, and means for causing the rings to operate the clamps, a shaft within this sleeve carrying a screw thread, having the pitch of the thread to be traced on the pipe, a feed block R carrying a female thread, and slidable betweenguides of the sleeve, and ada ted when advanced to engage the thread o the shaft, and provided with two abutments, and a rod S near one end supported and sliding through the forward ring C, and at another part of it having an incline adapted to engage between the abutments of the feed block for moving the latter relatively to the thread of the shaft, substantially as and for the purposes specified.

6. In mechanism for tracing pipe threads, the sleeve A, provided with clamps E, B, pivoted at B2 to the sleeve, and rings C slidable on the sleeves and against the clamps, and means for causing the rings to operate the clamps, a shaft within this sleeve carrying two or more screw threads of different pitch, said pitch being one of the kind which may, when desired, be traced upon the pipe, and feed blocks It, each having a female thread, located respectively opposite a screw thread of the shaft, and working in guides of the sleeve, and having abutments, and rods S, operating through the forward ring, and at rear each connected to its own feed block, and having an abutment, engaging the abutments of the feed block, for movin the latter relatively to the thread of the sha t, substantially as and for the pur poses specified.

7. In a mechanism for tracing pipe.

threads, a sleeve adapted to enter and be within the pipe to be operated on, a series of clamps located on the sleeve, and means for making them engage the pipe and hold the sleeve, a shaft within this sleeve carrying a thread having the pitch of the thread to be traced on the pipe, a feed block R carrying a female thread and held between guides of the sleeve, means for moving the feed block to and from the male thread of the shaft, and a rod for operating such last named means, a radially movable tool holder provided with the projection W, adapted to rest upon the adjacent portion of sleeve A, this portion of the sleeve being tapered, for thus enabling the tool holder to cut a taper upon the end of the pipe, substantially as and for the purposes specified.

8. In mechanism for tracing threads on pipes, the combination of a sleeve A, a shaft F therein, and connected thereto at its inner end, a shaft N located on shaft F and inside the sleeve A, gear wheel K connected to said shaft N, the arm G connected to said shaft F, a shaft H carried by arm G, hand crank at one end of the shaft H, and pinion J located at the other end of this shaft and engaging gear wheel K, slide tool rest located in the gear wheel K, spring L6 therefor, means X, X3, for setting the slide tool rest out of action, tool holder M, projection W of slide rest, adjusting screw L5, U, connected to holder M, and projection W, the sleeve A provided with taper A10 and the projection W adapted to rest thereon, the shaft N carrying threads O, P and Q, feed blocks It, working in guides S3, and adapted to engage their adjacent threads on the shaft N, rods S having inclines engaging the feed blocks, and working through one of the rin s C, the rings C, sliding on the sleeve clamps each having foot E and arm B pivoted together, abutments B3 on the sleeve A to which the arms B are respectively pivoted, the rings adapted to bear against their respective clamps, and bolt-s D, .and nuts, adapted for approximating the rings and moving the clamps, substantially as and for the purposes specified.

9. In a machine for chasing pipe threads, the combination of a rotatable frame, means for supporting it in axial alinement with the pipe to be threaded, guides in the frame, a slide rest movable therein, a sprlng lnterposed between the slide rest and frame and a cam lever pivoted to the slide rest and having one end arran ed to impinge against the frame, substantia y as and for the purposes specied.

10. In a machine for chasing pipe threads, the combination of a rotatable frame, means for supporting it in axial alinement with the pipe to be threaded, guides in the frame, a slide rest movable therein, guides in the slide rest, a tool holder slidable in the latter, a spring interposed between the slide rest and frame and a cam lever pivoted to the slide rest and having one end arranged to impinge against the frame, substantially as and for the purposes specified.

11. In mechanism for tracing threads on pipes, a cylindrical body, adapted to be partly located within the pipeto be traced, means for enabling this cylindrical body to be clamped to the pipe, a tool holder M and its tool, the latter being adapted to trace the thread on the pipe, an inner guide arm, a tapered form concentric with the pi e to be traced and stationary with the sai cylindrical bod and upon which the guide arm is adapte to rest, the tool holder being connected to this guide b an adjustin screw, and being adapted to e moved to an from said guide by said screw, and a sprin adapted to simultaneously press the too holder toward the pipe, and the guide toward its form, a support rotatably and longitudinally movable in the said cylindrical body, the spring, and tool holder, and guide being carried by the sup ort, and the spring tool holder and the said guide being movable in ways on the said support, substantially as and for the urposes specified.

12. In mechanism or tracing threads on pipes, a cylindrical body, adapted to be partly located within the pipe to be traced, means for enabling this cylindrical body to be clamped to the pi e, a tool holder M and its tool, the latter eing adapted to trace thread on the pipe, an lnner guide arm, a tapered form concentric with the pipe to be traced and stationary with the said cylindrical body and' upon which the guide arm is adapted to rest, the tool holder being connected to this guide by an adjusting screw, and being adapted to be moved to and irom said guide by said screw, and a the slide rest toward the aXis of said rotaspring adapted to simultaneously press the table frame, substantially as and for the purtool holder toward the pipe, and the guide poses specified. toward its form, a support rotatably and lll. In a machine for tracing threads on longitudinally movable in said cylindrical pipe, a frame rotatable and provided with body, the spring and tool holder and guide guides, a slide rest and holder L sliding on being carried by the support, and the spring, the guides of said frame, the slide rest and tool holder and said guide being movable in holder having guides for the tool holder M, Ways on the said support, and in combinathe latter being provided with guides engagtion with the slide rest and a stationary part ing the guides of the holder L, this slide of the frame the device for elevating the rest and holder L being provided with arm slide rest against the pressure of the spring W for engaging the pattern, screw U Whose and for holding it there, substantially as shoulder bears against arm W and rotatable and for the purposes specified. thereon, and Whose thread engages tool 13. In a machine for tracing threads on holder M, the spring between said sIide rest pipe, a frame rotatable and provided with and the said rotatable frame for depressing guides, a slide-rest and holder L sliding on the slide rest toward the axis of said rotathe guides of said frame, the slide rest and table frame, and the lever X pivoted at X4 holder having guides for the tool holder M, to the slide rest L, and the short arm' X3 the latter being provided with guides engagalso pivoted at X4 to the free end of the lever ing the guides of the holder L, this slide X, and abutment L7 against which said arm rest and holder L being provided With arm X3 impinges, substantially as and for the IV for engaging the pattern, screw U, Whose purposes specified.

shoulder is against arm W and rotatable WILLIAM T. JOHNSTON. thereon, and Whose thread engages tool Attest: holder M, the spring between said slide rest CHARLES A. MINTEN,

and the said rotatable frame for depressing K. SMITH. 

